The field of the invention relates generally to uninterrupted power supplies (UPS), and more specifically, isolated parallel ring buses for interconnected UPS systems including choke bypass switches.
Robust power systems enable supplying power to one or more loads. Such power systems may include combinations of generation, transport, rectification, inversion and conversion of power to supply energy for electronic, optical, mechanical, and/or nuclear applications and loads. When implementing power systems and architectures, practical considerations include cost, size, reliability, and ease of implementation.
In at least some known power systems, one or more uninterruptible power supplies (UPSs) facilitate supplying power to a load. UPSs facilitate ensuring that power is continuously supplied to one or more critical loads, even when one or more components of a power system fail. Accordingly, UPSs provide a redundant power source. UPSs may be utilized in a number of applications (e.g., utility substations, industrial plants, marine systems, high security systems, hospitals, datacomm and telecomm centers, semiconductor manufacturing sites, nuclear power plants, etc.). Further, UPSs may be utilized in high, medium, or low power applications. For example, UPSs may be used in relatively small power systems (e.g., entertainment or consumer systems) or microsystems (e.g., a chip-based system).
However, if a UPS fails or is malfunctioning, the load may not receive sufficient quality power to operate. In at least some known systems, multiple UPSs are coupled to a load to provide additional power redundancy. If one UPS fails, the other UPSs provide power to the load. In these known systems, the transient caused by a UPS failure can reduce the power quality of the power supplied to the load. For example, in systems with a power distribution unit (PDU) isolation transformer coupled between the UPSs and the load, isolating a fault from a failed UPS may saturate the PDU isolation transformer, which affects the power quality of the power supplied to the load.